SPP1 and lung cancer: Gathering current findings with previous studies on blood alterations of genomic and proteomic profiles in patients with COPD, AECOPD and lung cancer,1, 44, 45, 46 the increased circulating levels of OPN proteins and expression of OPN mRNA in leukocytes are associated with chronic airway stimuli, inflammation, and cancer development, with the disease progression and combination, and with the transfer from disease stages and severities.